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Ch08 system administration
- 1. Disks and File Systems Chapter 8
- 19. SCSI
- 32. SCSI
- 45. Disk Subsystems
Editor's Notes
- Need pictures here!!!
- If the bad spot is located on a cylinder which contains a “free” alternate sector, this is the preferred location to map the bad block. The drive electronics do not have to move the heads in this case. The only “penalty” is the delay caused by the rotational latency of the platter. On the other hand, if there is no free alternate sector on the same cylinder as the bad spot, there are penalties to be paid. The drive electronics have to move the heads to an alternate cylinder, and then write the data into the alternate location. The original bad spot has to be marked bad, and a table has to be updated to point to the new “alternate” location for the data from that sector. Every time the file is accessed, this penalty is paid.
- UPDATE THIS
- Pictures of the different raid levels!
- Add windows stuff here
- The entries in the table are created on a first-come, first-serve basis; there is no overlying structure to the table! The default size of the disk clusters is determined by the size of the partition. The minimum cluster size is 1 sector/cluster (512 bytes) for small (32 MB or smaller) partitions. The largest cluster size is 128 sectors (64 Kbytes) for large (2,048 to 4,096 MB) partitions. The operator can tune the cluster size using the format command with the /a:size switch when invoking format.
- Some UNIX variants also provide ufs logging. A file system that employs ufs logging is more fault tolerant than a standard ufs file system. The ufs logging feature allocates 1 megabyte of file system space per gigabyte of file system for use as a transaction log. The system disk driver writes all transactions to the log. Once the ufs log has been written, the driver considers the transaction complete. The information in the ufs log is written to the file system at a later time. Consult the manual page for mount_ufs for more information on ufs logging, and how to configure/enable it for specific versions of UNIX.
- Some UNIX variants also provide ufs logging. A file system that employs ufs logging is more fault tolerant than a standard ufs file system. The ufs logging feature allocates 1 megabyte of file system space per gigabyte of file system for use as a transaction log. The system disk driver writes all transactions to the log. Once the ufs log has been written, the driver considers the transaction complete. The information in the ufs log is written to the file system at a later time. Consult the manual page for mount_ufs for more information on ufs logging, and how to configure/enable it for specific versions of UNIX.
- Some UNIX variants also provide ufs logging. A file system that employs ufs logging is more fault tolerant than a standard ufs file system. The ufs logging feature allocates 1 megabyte of file system space per gigabyte of file system for use as a transaction log. The system disk driver writes all transactions to the log. Once the ufs log has been written, the driver considers the transaction complete. The information in the ufs log is written to the file system at a later time. Consult the manual page for mount_ufs for more information on ufs logging, and how to configure/enable it for specific versions of UNIX.
- Some UNIX variants also provide ufs logging. A file system that employs ufs logging is more fault tolerant than a standard ufs file system. The ufs logging feature allocates 1 megabyte of file system space per gigabyte of file system for use as a transaction log. The system disk driver writes all transactions to the log. Once the ufs log has been written, the driver considers the transaction complete. The information in the ufs log is written to the file system at a later time. Consult the manual page for mount_ufs for more information on ufs logging, and how to configure/enable it for specific versions of UNIX.
- Minix: the original Linux file system. Ext: The Extended file system ( ext ) was the replacement for the Minix file system on Linux. The ext file system came with a new concept: the virtual file system ( vfs ) driver. The vfs code allows the real file systems to interface with the kernel via an application-programming interface. This greatly simplified the task of porting new file systems to the Linux environment. Ext2: The Second Extended file system ( ext2 ) eventually replaced the ext file system on Linux. The ext2 file system continues to be the mainstay file system for Linux systems. Although it is similar to the ufs file system, it contains several modifications that improve performance and reliability of the overall file system. Ext3: The most recent version of the ext file system under Linux. Ext3 adds a configurable level of journaling to the features of the ext2 file system. Xia: The successor to the Minix file system. The Linux implementation allows Linux and Minim [Author: Minix?]to share files. Umsdos: A Linux version of the DOS file system. This file system provides additional structures for supporting file ownership, and security information for DOS file systems. Msdos: An implementation of the Microsoft DOS file system without the Linux extensions. Vfat: A Linux implementation of the Windows FAT file system. Proc: Refer to the UNIX file system section for information on the proc file system. Smb: The Microsoft Server Message Block file system for Linux. This file system allows Linux to mount Microsoft SMB file systems. Ncp: A Linux implementation of the Novel Client Protocol that allows Linux to mount Novel Netware file systems. Iso9660: The Linux implementation of the ISO9660 file system used by most CDs. Sysv: The Linux implementation of the original System V UNIX file system. Not used often. Hpfs: The Linux implementation of the High Performance File System, allowing Linux to mount OS/2 hpfs partitions. Affs: The Linux implementation of the Amiga fast file system that allows Linux and Amiga systems to share files. Ufs: Refer to the UNIX file systems section for information on the ufs file system.
- Minix: the original Linux file system. Ext: The Extended file system ( ext ) was the replacement for the Minix file system on Linux. The ext file system came with a new concept: the virtual file system ( vfs ) driver. The vfs code allows the real file systems to interface with the kernel via an application-programming interface. This greatly simplified the task of porting new file systems to the Linux environment. Ext2: The Second Extended file system ( ext2 ) eventually replaced the ext file system on Linux. The ext2 file system continues to be the mainstay file system for Linux systems. Although it is similar to the ufs file system, it contains several modifications that improve performance and reliability of the overall file system. Ext3: The most recent version of the ext file system under Linux. Ext3 adds a configurable level of journaling to the features of the ext2 file system. Xia: The successor to the Minix file system. The Linux implementation allows Linux and Minim [Author: Minix?]to share files. Umsdos: A Linux version of the DOS file system. This file system provides additional structures for supporting file ownership, and security information for DOS file systems. Msdos: An implementation of the Microsoft DOS file system without the Linux extensions. Vfat: A Linux implementation of the Windows FAT file system. Proc: Refer to the UNIX file system section for information on the proc file system. Smb: The Microsoft Server Message Block file system for Linux. This file system allows Linux to mount Microsoft SMB file systems. Ncp: A Linux implementation of the Novel Client Protocol that allows Linux to mount Novel Netware file systems. Iso9660: The Linux implementation of the ISO9660 file system used by most CDs. Sysv: The Linux implementation of the original System V UNIX file system. Not used often. Hpfs: The Linux implementation of the High Performance File System, allowing Linux to mount OS/2 hpfs partitions. Affs: The Linux implementation of the Amiga fast file system that allows Linux and Amiga systems to share files. Ufs: Refer to the UNIX file systems section for information on the ufs file system.
- The lines beginning with a pound sign (#) are considered comments and are used here to help delineate the various sections of the configuration information. The first two sections, beginning with the comments Database and Labels , describe the database routines and disk label types Volume Manager recognizes. These two sections should not be modified. “ Devices to use” Section The third section, marked by the comment Devices to use , lists the names and types of the removable media devices Volume Manager should monitor. Each line in this section starts with the keyword use , as follows. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 The use keyword is followed by the type of device, either CD-ROM or floppy, and the keyword drive , as follows. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 Following the device type is the OS name for the device. Note that the CD-ROM device name specifies only the first five characters of the full special device name. Because Volume Manager will monitor and mount all available slices it finds on a CD-ROM disk, the only information items needed are the specific controller and target portions of the device name. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 Following the special device name is the name of the shared object used to manage the device. This must match the device type specified (e.g., if the device type is cdrom , the shared object must be dev_cdrom.so ). Finally, the symbolic name used in the /device directory is listed. The first device of a given type has a 0 (zero) appended to its name, whereas the second is appended with a 1, and so on. For instance, a second CD-ROM drive located at target 5 on the built-in SCSI controller would be placed under Volume Manager control by adding the following line to the devices section of the vold.conf file. use cdrom drive /dev/dsk/c0t5 dev_cdrom.so cdrom1 Actions Section The next section, which begins with the comment Actions , specifies the actions to be taken when certain events occur. The basic events are the insertion of media into a drive ( insert ), removal of media from a drive ( eject ), and notification of problems ( notify ). An example entry in the actions section follows. eject /vol*/dev/diskette[0-9]/* user=root /usr/sbin/rmmount Entry Content Each line lists an event followed by a regular expression. When an event occurs, each line that begins with the name of the event ( insert , eject , or notify ) is checked. If the volume on which the event occurs matches the regular expression, the remainder of the action line comes into play. The remainder of this line includes the name of the user or group identification to be used to run the listed command with the listed arguments. In the previous example line, when the eject event occurs and the volume matches the regular expression /vol*/dev/diskette[0-9]/* , the command /usr/sbin/rmmount would be run with the root user permissions.
- The lines beginning with a pound sign (#) are considered comments and are used here to help delineate the various sections of the configuration information. The first two sections, beginning with the comments Database and Labels , describe the database routines and disk label types Volume Manager recognizes. These two sections should not be modified. “ Devices to use” Section The third section, marked by the comment Devices to use , lists the names and types of the removable media devices Volume Manager should monitor. Each line in this section starts with the keyword use , as follows. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 The use keyword is followed by the type of device, either CD-ROM or floppy, and the keyword drive , as follows. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 Following the device type is the OS name for the device. Note that the CD-ROM device name specifies only the first five characters of the full special device name. Because Volume Manager will monitor and mount all available slices it finds on a CD-ROM disk, the only information items needed are the specific controller and target portions of the device name. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 Following the special device name is the name of the shared object used to manage the device. This must match the device type specified (e.g., if the device type is cdrom , the shared object must be dev_cdrom.so ). Finally, the symbolic name used in the /device directory is listed. The first device of a given type has a 0 (zero) appended to its name, whereas the second is appended with a 1, and so on. For instance, a second CD-ROM drive located at target 5 on the built-in SCSI controller would be placed under Volume Manager control by adding the following line to the devices section of the vold.conf file. use cdrom drive /dev/dsk/c0t5 dev_cdrom.so cdrom1 Actions Section The next section, which begins with the comment Actions , specifies the actions to be taken when certain events occur. The basic events are the insertion of media into a drive ( insert ), removal of media from a drive ( eject ), and notification of problems ( notify ). An example entry in the actions section follows. eject /vol*/dev/diskette[0-9]/* user=root /usr/sbin/rmmount Entry Content Each line lists an event followed by a regular expression. When an event occurs, each line that begins with the name of the event ( insert , eject , or notify ) is checked. If the volume on which the event occurs matches the regular expression, the remainder of the action line comes into play. The remainder of this line includes the name of the user or group identification to be used to run the listed command with the listed arguments. In the previous example line, when the eject event occurs and the volume matches the regular expression /vol*/dev/diskette[0-9]/* , the command /usr/sbin/rmmount would be run with the root user permissions.
- The lines beginning with a pound sign (#) are considered comments and are used here to help delineate the various sections of the configuration information. The first two sections, beginning with the comments Database and Labels , describe the database routines and disk label types Volume Manager recognizes. These two sections should not be modified. “ Devices to use” Section The third section, marked by the comment Devices to use , lists the names and types of the removable media devices Volume Manager should monitor. Each line in this section starts with the keyword use , as follows. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 The use keyword is followed by the type of device, either CD-ROM or floppy, and the keyword drive , as follows. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 Following the device type is the OS name for the device. Note that the CD-ROM device name specifies only the first five characters of the full special device name. Because Volume Manager will monitor and mount all available slices it finds on a CD-ROM disk, the only information items needed are the specific controller and target portions of the device name. use cdrom drive /dev/dsk/c0t6 dev_cdrom.so cdrom0 Following the special device name is the name of the shared object used to manage the device. This must match the device type specified (e.g., if the device type is cdrom , the shared object must be dev_cdrom.so ). Finally, the symbolic name used in the /device directory is listed. The first device of a given type has a 0 (zero) appended to its name, whereas the second is appended with a 1, and so on. For instance, a second CD-ROM drive located at target 5 on the built-in SCSI controller would be placed under Volume Manager control by adding the following line to the devices section of the vold.conf file. use cdrom drive /dev/dsk/c0t5 dev_cdrom.so cdrom1 Actions Section The next section, which begins with the comment Actions , specifies the actions to be taken when certain events occur. The basic events are the insertion of media into a drive ( insert ), removal of media from a drive ( eject ), and notification of problems ( notify ). An example entry in the actions section follows. eject /vol*/dev/diskette[0-9]/* user=root /usr/sbin/rmmount Entry Content Each line lists an event followed by a regular expression. When an event occurs, each line that begins with the name of the event ( insert , eject , or notify ) is checked. If the volume on which the event occurs matches the regular expression, the remainder of the action line comes into play. The remainder of this line includes the name of the user or group identification to be used to run the listed command with the listed arguments. In the previous example line, when the eject event occurs and the volume matches the regular expression /vol*/dev/diskette[0-9]/* , the command /usr/sbin/rmmount would be run with the root user permissions.